Re: AM demodulation

[Barry Duggan]

Hi Bill,

Look at https://wiki.gnuradio.org/index.php/PLL_Carrier_Tracking. I 
think I will add this formula to the Notes: radians per sample = 2 * pi 
* freq / sample rate

I don't know how wide a spectrum the PLL can handle.

I am working on the documentation of blocks, so let me know if there is 
anything I need to add or clarify.

Cheers!
---
Barry Duggan KV4FV

P.S. I like the quote by Steve Sims :)

On 2019-10-28 10:44, Bill Dailey wrote:
> Can you give a little primer on using that PLL tracking?    I would
> love to use that to just track carriers random frequencies.  For
> instance 10mhz.  Ultimately I want to track and periodically log and
> offset from true predicted frequency. Like every 10 seconds.
>
> Bill Dailey
>
> Negativity always wins the short game. But positivity wins the long
> game. - Gary Vaynerchuk
>
> Don’t be easy to understand,
> Be impossible to misunderstand
> - Steve Sims
>
> > On Oct 28, 2019, at 9:27 AM, Barry Duggan <address@hidden> wrote:
> >
> > Hi Albin and Volker,
> >
> > I added a PLL Carrier Tracking block to take care of the tuning 
> > problem. See the revised 
> > https://wiki.gnuradio.org/index.php/File:FunCube_AM.png
> >
> > Albin, that 'spike' is the carrier! This is AM ;)
> >
> > Thank you both for your suggestions.
> > ---
> > Barry Duggan KV4FV
> >
> >
> > > On 2019-10-27 07:13, Albin Stigö wrote:
> > > Hi Barry,
> > > Some thoughts:
> > > You have a large DC spike at the center, try using the frequency 
> > > xlating
> > > fir filter to tune an offset frequency.
> > > Why don't you decimate at the channel filter?
> > > Try observing the signal at various points using the frequency sink.
> > > Good luck,
> > > Albin SM6WJM
> > > > On Sat, Oct 26, 2019, 21:02 Barry Duggan <address@hidden> wrote:
> > > > Hi,
> > > > I've been working on a gnuradio AM broadcast receiver, and have 
> > > > found
> > > > that the tuning is very critical to obtaining clear audio. My 
> > > > flowgraph
> > > > can be seen at 
> > > > https://wiki.gnuradio.org/index.php/File:FunCube_AM.png.
> > > > Are there any alternate demodulation methods which are not so 
> > > > sensitive
> > > > to exact tuning?
> > > > Thanks,
> > > > --
> > > > Barry Duggan KV4FV